Human and methods of diagnosis and treatment

Abstract

Human parvovirus, genus Bocavirus, associated with respiratory tract infections in children. Nucleic acid and polypeptide sequences of the virus. Methods and products for diagnosing presence of bocavirus in a sample using nucleic acid probes or primers, or specific binding members such as antibodies. Methods and products for diagnosing past or present infection of bocavirus in an individual e.g. by serology testing. Viral nucleic acid, polypeptide and/or viral particles for generating immune response in an individual, including vaccine compositions.

Description

The present application is §371 application of PCT/EP2006/008074 filed 16 Aug. 2006 which claims priority to US Provisional Application 60/737,576 filed 17 Nov. 2005, the entire disclosure of each being incorporated by reference herein.

Parvoviruses are capable of systemic infection of humans and other animals. Parvoviruses require proliferating host cells in order to replicate, so infection of respiratory and gut epithelium, hematopoietic cells, and transplacental infection of fetuses are frequent characteristics of parvoviruses. Parvovirus infections can therefore be associated with fetal infection and spontaneous abortion. They are also associated with respiratory tract infections. Lower respiratory tract infections (LRTI) are a leading cause of hospitalization of infants and young children.

The Parvoviridae family (“parvoviruses”) is divided into two subfamilies, Densovirinae infecting arthropods, and Parvovirinae, infecting birds and mammals. The viruses in the Parvovirinae subfamily have recently been reclassified into five genera by ICTV: Parvovirus, Erythrovirus, Dependovirus, Amdovirus and Bocavirus.

Previously known human parvoviruses are the well-known pathogen parvovirus B19 [1], including genotypes A6 and V9 (Erythrovirus), and the presumably apathogenic adeno-associated viruses (Dependovirus). Another virus isolate provisionally named human parvovirus 4 and detected in human blood was recently reported [2]. Its medical consequences are unknown.

Animal bocaviruses BPV (bovine parvovirus) and MVC (canine minute virus, or minute virus of canines) are associated with respiratory symptoms and enteritis of young animals. Systemic infection by BPV and MVC appears likely, and there are indications that fetal infection leading to fetal death may occur.

We have isolated and identified a new parvovirus. Specifically, the virus belongs to the Parvoviridae family, subfamily Parvovirinae, genus Bocavirus. We designate the virus “human bocavirus (HBoV)”. We believe this is only the second reported parvovirus species pathogenic to humans (after B19), and is the first reported human virus of the genus Bocavirus.

HBoV is associated with respiratory tract infections in children, which are frequently sufficiently severe to result in hospitalization. Thus, this virus explains a proportion of acute infections in children, the cause of which was previously unknown. HBoV may also be associated with other clinical manifestations.

The DNA sequences of the HBoV genome, and its encoded polypeptides, are disclosed herein. HBoV nucleotide sequences SEQ ID NOS 1 to 8 are shown in the appended sequence listing. Isolated nucleic acid molecules comprising one or more of these sequences, or their complementary sequences or fragments thereof, are aspects of the present invention. The nucleic acid molecules may for example be DNA or RNA.

HBoV sequences can be used to produce diagnostic materials for identifying or demonstrating the presence of the virus in a sample. Specific binding members e.g. antibodies to HBoV polypeptides may be produced.

HBoV nucleic acids and polypeptides may also be used to produce vaccines against HBoV, which may be administered to individuals, especially humans, such as babies, infants and children.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 Maps of the human bocavirus genome. A. Schematic map of isolate ST1 of HBoV showing the three open reading frames as arrows. They are: NS1, 1920 bp (183-2102), 639 a.a., NP-1, 660 bp (2340-2999), 219 a.a. and VP1/VP2, 2016 bp (2986-5001), 671 a.a. B. A map showing the location of the 26 nucleotide differences that were detected between two isolates of HBoV. The horizontal line represents the sequence of ST1, while each vertical line represents a nucleotide difference to ST2. In two cases where several differences were located close together, a longer vertical line representing four differences was used. The asterisks mark the three differences that resulted in a predicted amino acid change.

HBoV was identified from human respiratory tract samples using a system for large-scale molecular virus screening of clinical samples based on host DNA depletion, random PCR amplification, large-scale sequencing, and bioinformatics. Details of the methodology are described in [3] and [4], the contents of which are incorporated herein by reference. The samples included in the study were randomly selected nasopharyngeal aspirates submitted to Karolinska University Laboratory, Stockholm, Sweden for diagnostics of respiratory tract infections. Two pools of centrifuged, cell-free supernatants of anonymized nasopharyngeal aspirates were analyzed.

Parvovirus-like sequences were found in both libraries. They showed no significant similarity to database sequences at the nucleotide level in a BLAST search. However, the deduced amino acid sequence showed notable similarity with BPV and MVC, two related members of the Parvoviridae family, subfamily Parvovirinae, genus Bocavirus.

The individual source samples in the respective screening pool were identified by specific PCR targeting the sequence of the first detected clones. Using these samples as templates, we determined the complete coding consensus sequence of both index isolates: Stockholm 1 (ST1), 5217 nt, accession No DQ000495 [gi:66356128] and Stockholm 2 (ST2), 5299 nt, accession No DQ000496 [gi: 66356133].

Phylogenetic trees were constructed based on alignments of the isolates ST1 and ST2 and the viruses in the Parvovirinae subfamily. Results from full-length nucleotide sequences as well as nucleotide and deduced amino acid sequences of the two major open reading frames (ORFs) were consistent and confirmed that the isolates ST1 and ST2 group with MVC and BPV, as expected from the BLAST results. It has previously been recognized that MVC and BPV form a separate clade within the Parvovirinae, and the International Committee on Taxonomy of Viruses (ICTV) has recently assigned a separate genus with the name Bocavirus to BPV and MVC. The new virus is clearly separate from BPV and MVC, having only 43% amino acid identity to the nearest neighbor MVC in both major ORFs. The distance to BPV is remarkably similar: 42% amino acid identity in both major ORFs. We therefore conclude that the isolates ST1 and ST2 represent a previously unknown species of the genus Bocavirus.

The nucleotide sequence of HBoV genomic DNA of isolates ST1 and ST2 are shown in SEQ ID NO: 1 and SEQ ID NO: 2, respectively. The two HBoV isolates ST1 and ST2 are closely related, differing at only 26 nucleotide positions.

The genomic organization of HBoV closely resembles that of the other known bocaviruses BPV and MVC. Like in all members of the Parvovirinae subfamily, there are two major ORFs encoding a non structural protein (NS1) and at least 2 capsid proteins (VP1, VP2), respectively.

HBoV NS1 is encoded by nucleotides 183 to 2102 of SEQ ID NO: 1 and nucleotides 253 to 2172 of SEQ ID NO: 2, and has the amino acid sequence shown in SEQ ID NO: 3.

HBoV VP1 of ST1 is encoded by nucleotides 2986 to 5001 of SEQ ID NO: 1, and has the amino acid sequence shown in SEQ ID NO: 5.

HBoV VP1 of ST2 is encoded by nucleotides 3056 to 5071 of SEQ ID NO: 2, and has the amino acid sequence shown in SEQ ID NO: 7.

A second ORF within the ORF encoding VP1 begins at nucleotide position 3373 of SEQ ID NO: 1 and at nucleotide position 3443 of SEQ ID NO: 2. Nucleotides 3373 to 5001 of SEQ ID NO: 1 encode a second ST1 capsid protein VP2, which has the amino acid sequence shown in SEQ ID NO: 6. Nucleotides 3443 to 5071 of SEQ ID NO: 2 encode a second ST2 capsid protein VP2, which has the amino acid sequence shown in SEQ ID NO: 8.

Eighteen of the 26 nucleotide differences between the ST1 genomic DNA sequence SEQ ID NO: 1 and the ST2 genomic DNA sequence SEQ ID NO: 2, including the only three non-synonymous substitutions, occur in the capsid gene encoding VP1 and VP2 (FIG. 1B).

Like MVC and BPV, HBoV also has a third, middle ORF. In MVC and BPV this ORF encodes a non-structural protein with unknown function, named NP-1 [5, 6]. The mid ORF product NP-1 of HBoV is encoded by nucleotides 2340 to 2999 of SEQ ID NO: 1 and by nucleotides 2410 to 3069 of SEQ ID NO: 2, and has amino acid sequence SEQ ID NO: 4. HBoV NP-1 is homologous to MVC and BPV NP-1, having 47% amino acid identity to NP-1 of both MVC and BPV. This further supports the classification of HBoV as a Bocavirus.

HBoV polypeptides, including NS1, NP-1, VP1 and VP2 polypeptides as well as polypeptides with amino acid sequences at least 90, 95, 98 or 99% identity to the said NS1, NP-1, VP and VP2 polypeptides, form part of the invention, as do fragments e.g. peptide fragments of the polypeptides. Fragments are typically at least or about 10 amino acids in length, e.g. at least or about 15, 20, 25, 30, 35, 40, 50, 75, 100, 150 or 200 amino acids in length. For example, a fragment may be up to 200 amino acids in length, e.g. between 50 and 200 amino acids. Polypeptides comprising such fragments, and polypeptides and fragments that differ at one or more residues through substitution, addition or deletion, are also included in the invention.

HBoV nucleic acid molecules, nucleic acid molecules encoding polypeptides and fragments according to the invention, and nucleic acid molecules that specifically hybridise to nucleotide sequences disclosed herein are all aspects of the invention. The nucleic acid molecules may be provided as plasmids and vectors comprising the HBoV sequences (e.g. expression vectors, viral and non-viral vectors).

The nucleic acid and polypeptide sequences of HBoV constitute diagnostic keys to this virus. Nucleic acids and polypeptides of the virus described herein can be used as the basis for designing and/or producing diagnostic materials for determining whether an individual is or has been infected with HBoV, for example by testing for, identifying or demonstrating the presence of the virus in a sample, or by testing for the presence of anti-HBoV antibody in a sample.

Diagnostic assays can be performed to test for the presence of human bocavirus, or an antibody to human bocavirus, in a sample. Samples may be derived from individuals to be tested, especially babies or children, individuals with respiratory tract infections, blood donors and/or pregnant women. Samples may be taken from individuals suspected to be infected with parvovirus, especially bocavirus, and/or individuals with symptoms or conditions associated with parvoviral, especially bocavirus, infection, such as respiratory distress, wheezing, asthma, bronchitis, interstitial infiltrates (e.g. as indicated by chest X-ray) and/or fever. For diagnostic assays, a test sample may be provided in liquid form. A sample may be from the respiratory tract, e.g. a nasopharyngeal aspirate sample, or it may be e.g. a faecal or blood sample. Serological testing to determine the presence of anti-HBoV antibodies is normally done on blood samples.

In some embodiments of the invention, a sample is tested for HBoV by determining whether HBoV nucleic acid or polypeptide is present in the sample. Various methods are available to the skilled person for testing the sample, for example testing for hybridisation of HBoV nucleic acid to a specific primer or probe, or testing for binding of HBoV polypeptide to a specific binding member. Detection of the presence of HBoV nucleic acid or HBoV polypeptide in the sample indicates that the sample is positive for HBoV.

For example, the sample may be tested by being contacted with a specific binding member such as an antibody under appropriate conditions for specific binding. The binding member may optionally be labelled with a detectable label. Examples of suitable labels are described elsewhere herein. For example, the label may be a fluorescent label. Antibodies can be labelled with e.g. coloured latex, colloidal gold or colloidal selenium for detection by eye, or with an enzyme producing a detectable, e.g. coloured, product when a substrate is added. Binding may then be determined, e.g. using a reporter system. Where a panel of antibodies is used, different reporting labels may be employed for each antibody so that binding of each can be determined. Testing for binding of HBoV polypeptide to a specific binding member may employ e.g. immunofluorescence (IF), immunochromatography, or an enzyme immunoassay (EIA).

For example, a method of testing a sample for the presence of an HBoV polypeptide by determining binding to a binding member, e.g. antibody, may comprise:

• (i) providing a test sample, e.g. on a support e.g. an inert solid support such as a glass slide;
• (ii) contacting the test sample with binding members labelled with a detectable label e.g. a fluorescent label, under conditions in which the binding member binds to an HBoV polypeptide (if present) to form a binding member-polypeptide complex;
• (iii) washing the sample or support to remove any unbound binding member; and
• (iv) testing for the presence of the detectable label, wherein the presence of the detectable label indicates that the presence of HBoV polypeptide in the sample, i.e. that the sample is positive for human bocavirus.

Alternatively, a method of testing a sample for the presence of an HBoV polypeptide by determining binding to a binding member, e.g. antibody, may comprise:

• (i) providing a test sample, e.g. on a support e.g. an inert solid support such as a glass slide;
• (ii) contacting the test sample with a specific binding member against an HBoV polypeptide under conditions in which the binding member binds an HBoV polypeptide, if present, to form a binding member-polypeptide complex;
• (iii) washing the sample to remove any unbound specific binding member;
• (iv) contacting the sample with a second specific binding member, wherein the second specific binding member binds the said specific binding member against an HBoV polypeptide, if present, and wherein the second specific binding member is labelled with a detectable label, e.g. the second binding member may be a labelled anti-Ig antibody;
• (v) washing the sample to remove any unbound specific binding member; and
• (iv) testing for the presence of the detectable label, wherein the presence of the detectable label indicates the presence of HBoV polypeptide in the sample.

A sample may be fixed to the support for example by allowing the sample to dry on to the support.

Where the label is a fluorescent label, methods may comprise testing for fluorescence, e.g. by fluorescence microscopy. Alternatively, detection of the label may be by eye, where the label is visually detectable e.g. coloured latex, colloidal gold or colloidal selenium. Detection by enzyme-linked assay is also possible, where the binding member is labelled with an enzyme that produces a detectable, e.g. coloured, product when a substrate is added.

A method using EIA normally comprises:

• • providing a binding member, e.g. an antibody, against HBoV on a support, wherein the binding member may be immobilised on the support, and wherein the support is typically an inert solid such as a polystyrene plate (e.g. microtitre plate), a nitrocellulose membrane or microparticles e.g. latex microparticles or paramagnetic beads;
  • contacting the binding member with the test sample under conditions in which the binding member binds to an HBoV polypeptide (if present) to form a binding member-polypeptide complex;
  • washing the complex to remove any unbound protein and/or other compounds from the sample;
  • contacting the complex with a second binding member, e.g. antibody, against HBoV, wherein the second binding member is linked to an enzyme that catalyses conversion of a substrate to a detectable product, thereby forming a binding member-polypeptide-binding member-enzyme complex if polypeptide is present;
  • washing away any unbound second binding member; and
  • contacting the enzyme with the substrate and assaying for the presence of the detectable product;
  • wherein detection of the detectable product indicates the presence of HBoV polypeptide in the sample.

Alternatively, immunochromatography-type methods may be used to test a sample for the presence of an HBoV polypeptide. A method may comprise providing a device comprising a body, e.g. an absorbent membrane, on which one or more binding members, e.g. antibodies, against HBoV are supported, wherein a test sample is passable through the body by capillary flow such that the sample contacts the one or more binding members. The device may comprise a detection area for detection of binding member-polypeptide complexes. The device may be designed such that HBoV polypeptide present in the sample can bind a said binding member to form a binding member-polypeptide complex, wherein the complex accumulates in a designated area of the body of the device where it may be detected. A method may comprise allowing a test sample to pass through the body of the device by capillary flow, and determining whether a binding member-polypeptide complex is present in the detection area, wherein presence of the complex in the detection area indicates that HBoV polypeptide is present in the sample.

The device also forms an aspect of the present invention. The device may be disposable, e.g. it may be a single-use test device.

The binding members supported on the body of the device may be labelled or unlabelled. Where the binding members are labelled, the complex may be detected in the detection area by detecting the label. Accordingly, a method may comprise determining whether the label is present in the detection area. Where the binding members are unlabelled, the complex may be detected in the detection area by contacting the complex with a second binding member, wherein the second binding member is labelled with a detectable label, and wherein the second binding member binds to the complex e.g. to the HBoV polypeptide or to the binding member against HBoV.

Detectable labels are described elsewhere herein. Detection of the label may be by eye, where the label is visually detectable e.g. coloured latex, colloidal gold or colloidal selenium. Detection by enzyme-linked assay is also possible, where the binding member is labelled with an enzyme that produces a detectable, e.g. coloured, product when a substrate is added. The label may be a fluorescent label, detectable by detecting fluorescence e.g. by fluorescence microscopy.

A specific binding member such as an antibody may be used to isolate and/or purify its binding partner polypeptide from a test sample, to allow for sequence and/or biochemical analysis of the polypeptide to determine whether it has the sequence and/or properties of the polypeptide of interest, or if it is a mutant or variant form. Amino acid sequencing is routine in the art using automated sequencing machines.

Probes and primers can be used to identify human bocaviral nucleic acid in a sample. A method may include hybridisation of one or more (e.g. two) probes or primers to target nucleic acid in the sample. A test sample may be probed under conditions for selective hybridisation and/or subjected to a specific nucleic acid amplification reaction such as the polymerase chain reaction (PCR). A method may include hybridisation of one or more (e.g. two) probes or primers to target nucleic acid. The hybridisation may be as part of a PCR procedure e.g. as described in more detail below, or as part of a probing procedure not involving PCR.

Binding of a probe to target nucleic acid (e.g. DNA) may be measured using any of a variety of techniques at the disposal of those skilled in the art. For instance, probes may be radioactively, fluorescently or enzymatically labelled. Other methods not employing labelling of probe include examination of restriction fragment length polymorphisms, amplification using PCR or nucleic acid sequence based amplification (NASBA), ligase chain reaction (LCR), RNAase cleavage and allele specific oligonucleotide probing. Any of these methods, or any other suitable method, may be used to test a sample for the presence of HBoV nucleic acid.

NASBA is a method designed for amplification of RNA targets. An exponential amplification is achieved at stable 41° C. temperature by the activities of the enzymes AMV-RT, RNase H, and T7 DNA-dependent RNA polymerase. NASBA will amplify also DNA, in particular single stranded-DNA, and can be modified by the skilled person for use in the detection of HBoV DNA. Alternatively, NASBA can be used to identify replicating HBoV by identification of mRNA transcripts. NASBA is described in ref. [7].

LCR is an established method for molecular diagnostics and is an alternative to PCR. For LCR, the sample, or extracted DNA from the sample, is mixed with four oligonucleotide probes, which are complementary to a specific target region of HBoV, and thermostable ligase. The probes are designed to hybridize adjacently to each other on the target DNA, one pair to the sense strand, and the other pair to the antisense strand. In the presence of the template molecule they will be ligated to a longer molecule. By cycling the temperature this hybridization and ligation reaction will be repeated and the ligated product accumulated exponentially, and can be detected by a range of techniques, as for PCR.

Probing may employ the standard Southern blotting technique. For instance DNA may be extracted from cells and digested with different restriction enzymes. Restriction fragments may then be separated by electrophoresis on an agarose gel, before denaturation and transfer to a nitrocellulose filter. Labelled probe may be hybridised to the DNA fragments on the filter and binding determined. DNA for probing may be prepared from RNA preparations from cells. Those skilled in the art can employ suitable conditions of the desired stringency for selective hybridisation, taking into account factors such as oligonucleotide length and base composition, temperature and so on.

The skilled person is readily able to design suitable probes, label them and devise suitable conditions for the hybridisation reactions, assisted by textbooks such as Sambrook et al (1989) and Ausubel et al (1992). Those skilled in the art can employ suitable conditions of the desired stringency for selective hybridisation, taking into account factors such as oligonucleotide length and base composition, temperature and so on. Hybridisation may be performed under highly stringent conditions, such as 6×SSC at a temperature of 65° C. For oligonucleotide primers, hybridisation may be performed under hybridising conditions for PCR, e.g. at 54° C.

Nucleic acid probes and oligonucleotide primers may be produced that specifically hybridise to human bocaviral nucleic acids including nucleic acid molecules comprising nucleotide sequences described herein. The bocavirus genome may be present as a plus- or minus-stranded single-stranded DNA molecule in virus particles or infected cells. The probe or primer may hybridise to a nucleic acid molecule with a nucleotide sequence described herein or to a nucleic acid molecule with a nucleotide sequence that is the complement of any of the sequences described herein. Assays may be for detecting detect mRNA or genomic DNA of bocavirus, where genomic DNA may comprise nucleotide sequences shown herein or the complement thereof. For example, oligonucleotide or polynucleotide fragments of SEQ ID NO: 1 or SEQ ID NO: 2 or the complementary sequence thereof can be used as primers or probes. Such primers and probe sequences may be modified by addition, substitution, insertion or deletion of one or more nucleotides, and the skilled person will be able to design suitable modified sequences that retain ability to hybridise with the target sequence.

PCR may be used to test for, identify or demonstrate the presence of human bocaviral nucleic acid in a sample. Such an assay may be used diagnostically to determine whether an individual is infected with HBoV. PCR involves use of a pair of primers, termed “forward” and “reverse” primers, which hybridise specifically to two complementary target nucleic acid strands, respectively. Thus, one primer may specifically hybridise to SEQ ID NO: 1 or SEQ ID NO: 2 and the second primer may specifically hybridise to the complement of SEQ ID NO: 1 or SEQ ID NO: 2.

PCR techniques for the amplification of nucleic acid are described in refs 8, 9, 10, 11 and 12. PCR comprises steps of denaturation of template nucleic acid (where necessary, for a double-stranded template), annealing of primers to target nucleic acid, and polymerisation of target nucleic acid to produce a specific DNA product corresponding to the nucleic acid located between (and including) the forward and reverse primers. The product is amplified through repetition of these steps. PCR can thus be used to amplify specific sequences from genomic DNA or specific RNA sequences.

HBoV has a single stranded DNA genome. PCR of HBoV nucleic acid involves (i) first primer hybridisation, in which one primer binds to HBoV nucleic acid, (ii) polymerisation from first primer to produce DNA strand complementary to initial HBoV nucleic acid strand, (iii) denaturation to separate complementary strands and primers, (iv) hybridisation of first and second primer to complementary target nucleic acid strands, whereby second primer hybridises to complementary strand synthesised from first primer, (v) polymerisation from first and second primer, (vi) repetition of steps (iii)-(v) for a suitable number of cycles.

Primers may hybridise specifically to HBoV nucleic acid encoding NP-1, e.g. to a sequence of nucleotides 2340 to 2999 shown in SEQ ID NO: 1 and nucleotides 2410 to 3069 shown in SEQ ID NO: 2. Example primer sequences hybridise to the N-terminal region of NP-1, e.g. the primers shown in SEQ ID NO: 9 and SEQ ID NO: 10.

The skilled person can select a suitable length nucleic acid to use as a PCR primer. For example, an oligonucleotide primer may be at least 10, 12 or 15 nucleotides in length. Preferably an oligonucleotide primer has a length of 30, 27 or 24 nucleotides or less. For example, it may be about 12, 15, 18, 21 or 24 nucleotides in length.

Preferably, the forward and reverse primers hybridise within a distance of 500 nucleotides from each other, and thereby define a region of 500 nucleotides or less for amplification by PCR. Thus, the specific nucleotide sequence to which the forward primer hybridises is within 500 nucleotides of the specific nucleotide sequence to which the reverse primer hybridises on the complementary strand.

An assay may detect human bocavirus nucleic acid, e.g. nucleic acid comprising a nucleotide sequence as shown herein, using one or more nucleic acid probes or primers that hybridise specifically to human bocavirus nucleic acid.

In a preferred embodiment, an assay method comprises providing a test sample, and testing for the presence of human bocavirus nucleic acid in the sample using PCR with oligonucleotide primers that hybridise specifically to human bocavirus nucleotide sequences. The assay may comprise adding oligonucleotide PCR primers to the sample, placing the sample in conditions for PCR, and then testing the sample for the presence of a PCR product. Conditions for PCR preferably include at least 20, 25, 30 or 35 PCR cycles. Detection of PCR product, e.g. by visualisation of a band of the expected size following gel electrophoresis of the sample, indicates that the sample is positive for human bocavirus nucleic acid. As an additional check, the PCR-product may be sequenced in order to confirm that it is bocaviral nucleic acid. Absence of a PCR product indicates that the sample is negative for human bocavirus nucleic acid.

Preferably, the assay is capable of detecting multiple isolates of HBoV, and primers directed to the NP-1 ORF of human bocaviral nucleic acid may thus be preferred.

Example 1 below describes in detail the performance of PCR assay methods according to an embodiment of the invention.

Methods of the invention may comprise detecting the presence of HBoV polypeptide or nucleic acid in a sample and thus concluding that the sample is positive for human bocavirus, indicating that the individual from whom the sample was obtained is infected with bocavirus.

Further aspects of the invention are kits for testing a sample for the presence of human bocavirus, e.g. testing for HBoV nucleic acid or HBoV polypeptide in a sample. For example, a kit for testing a sample for an HBoV polypeptide may be for use in a method of determining whether a polypeptide in a sample binds to a specific binding member, as described above.

A kit may comprise specific binding members for one or more HBoV polypeptides e.g. antibody molecules, which may be labelled with a detectable label, or may be unlabelled. Examples of suitable detectable labels are described elsewhere herein. The specific binding members may be provided in solution, e.g. packaged in a container e.g. a phial. A kit may comprise unlabelled specific binding members, e.g. antibodies, for an HBoV polypeptide, and labelled specific binding members that bind the unlabelled specific binding members, e.g. anti Ig antibodies. Labelled and unlabelled binding members may be provided in separate containers e.g. phials. Where the label is an enzyme that catalyses conversion of a substrate to a detectable product, a kit may further comprise a suitable enzyme substrate for detection of the label. For example, the kit may comprise a container e.g. a bottle or phial comprising substrate for the enzyme, typically a solution, which may be provided at a suitable concentration for use in EIA.

A kit may comprise a device for testing a sample for human bocavirus, the device comprising a body on which one or more specific binding members for an HBoV polypeptide are supported, wherein a test sample is passable through the body by capillary flow such that the sample contacts the one or more binding members to form a binding-member polypeptide complex if HBoV polypeptide is present in the sample, and wherein the body also comprises a detection area for detection of the binding member-polypeptide complexes. The binding members may be labelled or unlabelled. The device may be a single-use test device for an immunochromatography assay, on which a sample is to be provided, and containing e.g. labelled or unlabelled specific binding members for HBoV polypeptides. The kit may further comprise phials of diluents, and/or labelled or unlabelled specific binding members for HBoV polypeptides e.g. antibody molecules, e.g. provided in solution, as described above.

A kit may comprise specific binding members for one or more HBoV polypeptides, wherein the binding members are immobilised on a support. The support is preferably an inert solid such as a polystyrene plate (e.g. microtitre plate), a nitrocellulose membrane or microparticles e.g. latex microparticles or paramagnetic beads. Normally the binding members bound to the support are unlabelled.

Washing solution or solutions, for washing away unbound protein, other compounds from the sample, or unbound binding member, may also be included in kits, normally in one or more containers e.g. bottles or phials. Normally the elements of a kit e.g. support; labelled binding member; unlabelled binding member; substrate and/or washing solution are separately contained in the kit e.g. provided in separate packages or containers from one another. A kit may also include one or more articles and/or reagents for performance of the method, such as means for providing the test sample itself, e.g. a swab for removing cells from the buccal cavity or a syringe for removing a blood sample (such components generally being sterile). A kit may further comprise a support, e.g. an inert solid support such as a glass slide, on which a sample is to be provided. As will be apparent to the skilled person, components included in the kit will depend on the nature of the method for which it is intended.

Nucleic acid primers may be provided as part of a kit, e.g. in a suitable container. The primers are typically provided in separate containers within a kit package, and are normally in the form of sterile solutions. The kit may include instructions for use of the nucleic acid, e.g. in PCR and/or a method for determining the presence of nucleic acid of interest in a test sample. A kit wherein the nucleic acid is intended for use in PCR may include one or more other reagents required for the reaction, such as polymerase, nucleosides, buffer solution etc. The nucleic acid may be labelled. A kit for use in determining the presence or absence of nucleic acid of interest may include one or more articles and/or reagents for performance of the method, such as means for providing the test sample itself, e.g. a swab for removing cells from the buccal cavity or a syringe for removing a blood sample (such components generally being sterile).

HBoV polypeptides can also be used to investigate whether an individual has antibodies for HBoV. The presence of antibodies for HBoV indicates that the individual is or has been infected with HBoV. Accordingly, an aspect of the invention relates to testing of a sample for the presence of antibody to one or more HBoV polypeptides, preferably antibody for VP1 and/or VP2, by determining whether antibodies in the sample bind to one or more HBoV polypeptides. Normally, the sample is a blood sample. The method typically comprises providing an HBoV polypeptide on a support. Normally the polypeptide is immobilised on the support. The support is typically an inert solid such as a polystyrene plate (e.g. microtitre plate), a nitrocellulose membrane or microparticles e.g. latex microparticles or paramagnetic beads. The method generally further comprises contacting the HBoV polypeptide with the test sample under conditions in which the HBoV polypeptide binds to an antibody for HBoV (if present) to form a polypeptide-antibody complex; and determining or testing for formation of a polypeptide-antibody complex. Normally, the support is washed after contacting the HBoV polypeptide with the sample, to remove any unbound protein and/or other compounds from the sample.

Determining or testing for formation of the complex may comprise contacting the complex with a detectably-labelled antibody, which may be specific for immunoglobulin, e.g. directed against the Fc domain of IgG. Any unbound anti-Ig antibody is then normally washed away, before assaying for the presence of the detectably-labelled antibody bound to the complex. Detection of the labelled antibody indicates the presence of antibody against HBoV polypeptide in the sample.

Normally, an enzyme immunoassay EIA is used to detect the labelled antibody. Thus, the anti-Ig antibody may be linked to an enzyme that catalyses conversion of a substrate to a detectable product. There is a range of detection systems for EIA and other immunoassays available to the skilled person, such as alkaline phosphatase, peroxidase and chemoilluminescent assays. Assaying for the presence of the labelled antibody may comprise contacting the enzyme with the substrate and assaying for the presence of the detectable product. The product can be detected by eye or in an instrument designed for the purpose, for example a spectrophotometer designed for microtitre plates or a large multipurpose clinical laboratory assay instrument.

For analysis of human samples, the anti-Ig antibody is normally specific for the Fc region of human immunoglobulins, e.g human IgG or IgM.

Materials for detecting anti-HBoV antibody in a sample may be provided in kit form. Preferably the kit is for use in a method comprising EIA, e.g. as described above. A kit may comprise an HBoV polypeptide e.g. HBoV VP1 or VP2, or more than one HBoV polypeptide, bound to a support. Normally the polypeptide is immobilised on the support. The support is preferably an inert solid such as a polystyrene plate (e.g. microtitre plate), a nitrocellulose membrane or microparticles e.g. latex microparticles or paramagnetic beads. The kit may also comprise antibody specific for immunoglobulin, e.g. the Fc domain of anti-IgG, wherein the anti-Ig antibody is detectably labelled. For example it may be linked to an enzyme that catalyses conversion of a substrate to a detectable product. The kit may comprise a container e.g. a bottle or phial comprising substrate for the enzyme, typically a solution, and preferably at a suitable concentration for use in EIA, e.g. ELISA. Washing solution or solutions, for washing away unbound protein, other compounds from the sample, or unbound anti-Ig antibody, may also be included in the kit, normally in one or more containers e.g. bottles or phials. Normally the elements of the kit e.g. polypeptide on support; anti-Ig antibody; substrate and/or washing solution are separately contained in the kit e.g. provided in separate packages or containers from one another.

Specific binding members for HBoV can be produced by the skilled person. A specific binding member for HBoV binds specifically to an epitope on HBoV, typically to an HBoV polypeptide. For example, a specific binding-member may be an antibody molecule or a non-antibody protein that comprises an antigen-binding site. The term “specific” as used herein generally refers to the situation in which a specific binding member does not show any significant binding to molecules other than its specific binding partner(s). The term is also applicable where e.g. an antigen-binding site is specific for a particular epitope that is carried by a number of antigens, in which case the specific binding member carrying the antigen-binding site will be able to bind to the various antigens carrying the epitope.

Preferably, the specific binding member is for an HBoV polypeptide encoded by a nucleic acid molecule shown herein, such as NS1, NP-1, VP1 or VP2. Preferably, the specific binding molecule is for HBoV capsid protein e.g. VP1 and/or VP2.

Typically, the specific binding member is an antibody molecule. The term “antibody” describes an immunoglobulin whether natural or partly or wholly synthetically produced. The term also covers any polypeptide or protein comprising an antibody antigen-binding site. The term “antigen-binding site” describes the part of a molecule that binds to and is complementary to all or part of the target antigen. In an antibody molecule it is referred to as the antibody antigen-binding site, and comprises the part of the antibody that specifically binds to and is complementary to all or part of the target antigen. Where an antigen is large, an antibody may only bind to a particular part of the antigen, which part is termed an epitope. An antibody antigen-binding site may be provided by one or more antibody variable domains. Preferably, an antibody antigen-binding site comprises an antibody light chain variable region (VL) and an antibody heavy chain variable region (VH). Antibody molecules and fragments that comprise an antibody antigen-binding site include Fab, scfv, Fv, dAb, Fd, minibodies and diabodies. As antibodies can be modified in a number of ways, the term “antibody molecule” should be construed as covering any specific binding member or substance having an antibody antigen-binding site with the required specificity. Thus, this term covers antibody fragments and derivatives, including any polypeptide comprising an antibody antigen-binding site, whether natural or wholly or partially synthetic. Chimeric molecules comprising an antibody antigen-binding site, or equivalent, fused to another polypeptide are therefore included. Cloning and expression of chimeric antibodies are described in EP-A-0120694 and EP-A-0125023, and a large body of subsequent literature.

For therapeutic use the specific binding member is preferably a human or humanized antibody molecule. Various techniques for generating human or humanized antibodies are available [13, 14, 15]. Binding members for diagnostic use are normally monoclonal or polyclonal antibodies derived from laboratory animals.

Alternatively, an antigen binding site may be provided by means of arrangement of complementarity determining regions (CDRs) on non-antibody protein scaffolds such as fibronectin or cytochrome B, or by randomising or mutating amino acid residues of a loop within a protein scaffold to confer binding specificity for a desired target [16, 17]. The scaffold may be a human or non-human protein.

A specific binding member of the invention may carry a detectable label, such as an enzyme that catalyses a reaction producing a detectable product, e.g. for use in EIA. Other detectable labels include for example fluorescent labels, radiolabels, biotin, coloured latex, colloidal gold or colloidal selenium.

Compounds that bind to HBoV polypeptides, including specific binding members for HBoV polypeptides, and inhibitors of HBoV polypeptides, may be identified by screening candidate agents e.g. from compound libraries. For example, a method of identifying a compound that binds an HBoV polypeptide may comprise exposing an HBoV polypeptide or a fragment thereof to a test agent, and determining whether the test agent binds to the HBoV polypeptide or fragment thereof. Preferably the HBoV polypeptide is VP1 or VP2 or an extracellular domain or fragment of VP1 or VP2. The method may further comprise determining whether the test agent inhibits the function of the HBoV polypeptide, for example whether the agent inhibits the ability of HBoV to infect a cell e.g. in an in vitro assay. Compounds that bind HBoV polypeptide, including specific binding members and inhibitors, may be useful as antiviral therapeutics for treating or preventing HBoV infection. Such a compound may be formulated into a composition comprising a pharmaceutically acceptable excipient.

An HBoV nucleic acid, polypeptide or fragment according to the invention may be used for raising an immune response in an individual, for example for generating antibodies against HBoV polypeptides. Alternatively, HBoV particles, or purified fragments thereof, may be used for raising an immune response in an individual, for example for generating antibodies against HBoV polypeptides. For example live e.g. live attenuated, or killed, e.g. formalin inactivated, HBoV may be used. HBoV particles may be composed of a single copy of the HBoV genome as a single-stranded DNA, surrounded by the virus capsid. The capsid may comprise VP1 and VP2, of which VP2 may be the main component.

An HBoV particle or purified fragment thereof and/or an HBoV nucleic acid molecule, polypeptide or fragment thereof may be formulated into a composition comprising a pharmaceutical excipient, e.g. formulated for administration by injection. Adjuvant may also be included in the composition. The nucleic acid may be packaged e.g. in a liposome or may be free in solution. HBoV nucleic acid molecules, polypeptides or fragments thereof for may be provided by, contained as part of, or isolated from HBoV particles e.g. attenuated or killed HBoV e.g. formalin inactivated HBoV, or may be recombinantly produced. For example, VP1 and/or VP2 may be expressed in a recombinant system to produce and virus-like particles (VLPs), and VLPs may be formulated into a composition comprising a pharmaceutical excipient, e.g. formulated for administration by injection. The compositions may be used for inducing an immune response, for example for raising antibodies and/or for vaccination of individuals against HBoV.

Specific binding members, polypeptides, nucleic acid molecules and fragments according to the invention are normally provided in isolated form. The term “isolated” means that they are normally free or substantially free of material with which they are naturally associated such as other polypeptides or nucleic acids with which they are found in their natural environment, or the environment in which they are prepared (e.g. cell culture) when such preparation is by recombinant DNA technology practised in vitro or in vivo. They may be formulated with diluents or adjuvants and still for practical purposes be isolated—for example specific binding members will normally be mixed carriers if used to coat microtitre plates for use in immunoassays, or will be mixed with pharmaceutically acceptable carriers or diluents when used in diagnosis or therapy. Specific binding members may be glycosylated or unglycosylated.

The following non-limiting examples are for purposes of illustration only.

EXAMPLES

Example 1

Diagnostic PCR for Human Bocavirus

Experiments were performed in a diagnostic laboratory setting, ensuring that necessary precautions to avoid contamination were taken. Samples were screened in pools of ten, and for PCR-positive pools, samples were extracted and amplified individually. Positive and negative controls were included in each experiment. DNA was extracted by QIAamp DNA Blood Mini Kit (Qiagen). Five μl extracted DNA was used as template for the PCR reaction. The 50 μl reaction mix consisted of 1× GeneAmp PCR buffer II (Applied Biosystems) (100 mM Tris-HCl pH 8.3, 500 mM KCl), 2.5 mM MgCl₂, 0.2 mM each dNTP, 20 pmol each of the primers 188F(GAGCTCTGTAAGTACTATTAC—SEQ ID NO: 9) and 542R (CTCTGTGTTGACTGAATACAG—SEQ ID NO: 10), and 2.5 U of AmpliTaq Gold DNA polymerase (Applied Biosystems). After 10 min at 94° C., 35 cycles of amplification (94° C. 1 min, 54° C. 1 min, 72° C. 2 min) were performed. Products were visualized on an agarose gel. The expected product size was 354 bp. All PCR-products were sequenced in order to confirm that they were specific for HBoV.

Example 2

Incidence and Symptoms of Human Bocavirus Infection

In order to estimate the prevalence of HBoV in respiratory tract samples and the clinical picture associated with HBoV-infection, a series of PCR screening experiments was performed. As a first overview, 378 culture-negative nasopharyngeal aspirate samples drawn from November 2003 through September 2004 were screened for HBoV by a PCR assay targeting 354 base pairs in the NP-1 gene. These samples came from various clinics served by the Karolinska University Laboratory. 266 samples were from pediatric patients and 112 from adult patients. Seven samples were positive for HBoV DNA and all seven came from infants and children.

Therefore, a more detailed retrospective study was performed in the pediatric infectious diseases ward at the Karolinska University Hospital. All 540 available nasopharyngeal aspirates drawn in the ward (hospitalized patients only) from November 2003 through October 2004 were investigated, including some of the samples included in the first screening. Samples from 17 different patients (3.1%) were positive. The HBoV specificity of the PCR products was confirmed by sequencing. Fourteen HBoV-positive samples were negative for other viruses investigated (by IF and virus culture), while HBoV was detected along with another virus in 3 cases (two RSV, one adenovirus). Morbidity from LRTI is highest in the winter season, and this was reflected by sampling frequency as well as findings of HBoV (Table 1).

The medical records of the 14 patients infected with HBoV only were reviewed. All 14 children were admitted from home with respiratory distress of 1-4 days duration. Seven children had a history of wheezing bronchitis/asthma and were under daily treatment with inhaled beta-2-stimulans and steroids. Four of them had previously been hospitalized for wheezing bronchitis. Two children had chronic lung disease that originated in the neonatal period, and five patients had no history of previous respiratory tract problems. All patients had variable degree of respiratory distress, and fever was prevalent. Chest x-ray demonstrated interstitial bilateral infiltrates in 6 of 7 cases. Gastrointestinal symptoms, conjunctivitis or rash was not recorded in any case.

In order to establish that HBoV was the likely etiologic agent of the observed symptoms, and not just a coincidental finding, we investigated how findings of HBoV correlated to findings of other likely etiologic agents. In the 540 samples analyzed, a known viral pathogen (mainly influenza A virus or RSV) was identified by standard diagnostics (IF and virus culture) in 258 of the 540 patients (48%), and no virus was found by standard diagnostics in 282 patients (52%). 14 of the 17 HBoV findings were in the latter group. Thus, HBoV was primarily found in samples negative for other viruses (p<0.01, Fisher's exact test), providing an indication that it is an etiologic agent of LRTI in our patients.

Table 1

Findings of HBoV in nasopharyngeal aspirate samples drawn in the pediatric infectious diseases unit November 2003-October 2004 distributed per month.

	Month	Tested	Positive
	Nov	28	0
	Dec	125	4
	Jan	100	5
	Feb	110	4
	Mar	85	1
	Apr	43	2
	May	12	0
	Jun	4	1
	Jul	11	0
	Aug	3	0
	Sep	12	0
	Oct	7	0
	Total	540	17

Sequences

SEQ ID NO: 1 HBoV ST1 genomic DNA
1    caaggaggag tggttatatg atgtaatcca taaccactcc caggaaatga cgtatgatag
61   ccaatcagaa ttgagtattg aacctatata agctgctgca cttcctgatt caatcagact
121  gcatccggtc tccggcgagt gaacatctct ggaaaaagct ccacgcttgt ggtgagtcta
181  ctatggcttt caatcctcct gtgattagag ctttttctca acctgctttt acttatgtct
241  tcaaatttcc atatccacaa tggaaagaaa aagaatggct gcttcatgca cttttagctc
301  atggaactga acaatctatg atacaattaa gaaactgcgc tcctcatccg gatgaagaca
361  taatccgtga tgacttgctt atttctttag aagatcgcca ttttggggct gttctctgca
421  aggctgttta catggcaaca actactctca tgtcacacaa acaaaggaat atgtttcctc
481  gttgtgacat catagttcag tctgagctag gagagaaaaa cttacactgc catattatag
541  ttgggggaga aggactaagc aagaggaatg ctaaatcatc ctgtgctcag ttctatggtt
601  taatactagc tgaaataatt caacgctgca aatctcttct ggctacacgt ccttttgaac
661  ctgaagaggc tgacatattt cacactttaa aaaaggctga gcgagaggca tggggtggag
721  ttactggcgg caacatgcaa atccttcaat atagagatcg cagaggagac cttcatgcac
781  aaacagtgga tcctcttcgc ttcttcaaaa actacctttt acctaaaaat agatgtattt
841  catcttacag caaacctgat gtttgtactt ctcctgacaa ctggttcatt ttagctgaaa
901  aaacttactc tcacactctt attaacgggc tgccgcttcc agaacattac agaaaaaact
961  accacgcaac cctagataac gaagtcattc cagggcctca aacaatggcc tatggaggac
1021 gtggtccgtg ggaacatctt cctgaggtag gagatcagcg cctagctgcg tcttctgtta
1081 gcactactta taaacctaac aaaaaagaaa aacttatgct aaacttgcta gacaaatgta
1141 aagagctaaa tctattagtt tatgaagact tagtagctaa ttgtcctgaa ctactcctta
1201 tgcttgaagg tcaaccagga ggggcacgcc ttatagaaca agtcttgggc atgcaccata
1261 ttaatgtttg ttctaacttt acagctctca catatctttt tcatctacat cctgttactt
1321 cgcttgactc agacaataaa gctttacagc ttttgttgat tcaaggctat aatcctctag
1381 ccgttggtca cgccctgtgc tgtgtcctga acaaacaatt cgggaaacaa aacactgttt
1441 gcttttacgg gcctgcctca acaggtaaaa caaatatggc caaggcaatc gtccaaggga
1501 ttagacttta tgggtgtgtt aatcatttga acaaaggatt tgtatttaat gactgcagac
1561 aacgcttagt tgtttggtgg gaggagtgct taatgcacca ggattgggtg gaacctgcaa
1621 agtgtatctt gggcgggaca gaatgcagaa ttgacgtcaa gcatagagac agtgtacttt
1681 taactcaaac acctgtaatt atatccacta accacgatat ctacgcggtt gttggtggca
1741 attctgtttc tcatgttcac gcggctccat taaaagaaag agtgattcag ctaaatttta
1801 tgaaacaact tcctcaaaca tttggagaaa tcactgctac tgagattgca gctcttctac
1861 agtggtgttt caatgagtac gactgtactc tgacaggatt taaacaaaaa tggaatttag
1921 ataaaattcc aaactcattt cctcttgggg tcctttgtcc tactcattca caggacttta
1981 cacttcacga aaacggatac tgcactgatt gcggtggtta ccttcctcat agtgctgaca
2041 attctatgta cactgatcgc gcaagcgaaa ctagcacagg agacatcaca ccaagtaagt
2101 aaatacgcat gcgcaagtaa ttcttttact ttcacttcgc tatttttacc aatttttact
2161 tttaggtgac ttgggggatt cggacggaga agacaccgag cctgagacat cgcaagtgga
2221 ctattgtcca cccaagaaac gtcgtctaac tgctccagca agtcctccaa actcacctgc
2281 gagctctgta agtactatta ctttctttaa cacttggcac gcacagccac gtgacgaaga
2341 tgagctcagg gaatatgaaa gacaagcatc gctcctacaa aagaaaaggg agtccagaaa
2401 gaggggagag gaagagacac tggcagacaa ctcatcacag gagcaggagc cgcagcccga
2461 tccgacacag tggggagaga ggctcgggct catatcatca ggaacaccca atcagccacc
2521 tatcgtcttg cactgcttcg aagacctcag accaagtgat gaagacgagg gagagtacat
2581 cggggaaaaa agacaataga acaaatccat acactgtatt cagtcaacac agagcttcca
2641 atcctgaagc tccagggtgg tgtgggttct actggcactc tactcgcatt gctagagatg
2701 gtactaattc aatctttaat gaaatgaaac aacagtttca acagctacaa attgataata
2761 aaataggatg ggataacact agagaactat tgtttaatca aaagaaaaca ctagatcaaa
2821 aatacagaaa tatgttctgg cactttagaa ataactctga ttgtgaaaga tgtaattact
2881 gggatgatgt gtaccgtagg cacttagcta atgtttcctc acagacagaa gcagacgaga
2941 taactgacga ggaaatgctt tctgctgctg aaagcatgga agcagatgcc tccaattaag
3001 agacagccta gagggtgggt gctgcctgga tacagatatc ttgggccatt taatccactt
3061 gataacggtg aacctgtaaa taacgctgat cgcgctgctc aattacatga tcacgcctac
3121 tctgaactaa taaagagtgg taaaaatcca tacctgtatt tcaataaagc tgatgaaaaa
3181 ttcattgatg atctaaaaga cgattggtca attggtggaa ttattggatc cagttttttt
3241 aaaataaagc gcgccgtggc tcctgctctg ggaaataaag agagagccca aaaaagacac
3301 ttttactttg ctaactcaaa taaaggtgca aaaaaaacaa aaaaaagtga acctaaacca
3361 ggaacctcaa aaatgtctga cactgacatt caagaccaac aacctgatac tgtggacgca
3421 ccacagaacg cctcaggggg aggaacagga agtattggag gaggaaaagg atctggtgtg
3481 gggatttcca ctggagggtg ggtcggaggt tctcactttt cagacaaata tgtggttact
3541 aaaaacacaa gacaatttat aaccacaatt cagaatggtc acctctacaa aacagaggcc
3601 attgaaacaa caaaccaaag tggaaaatca cagcgctgcg tcacaactcc atggacatac
3661 tttaacttta atcaatacag ctgtcacttc tcaccacaag attggcagcg ccttacaaat
3721 gaatataagc gcttcagacc taaagcaatg caagtaaaga tttacaactt gcaaataaaa
3781 caaatacttt caaatggtgc tgacacaaca tacaacaatg acctcacagc tggcgttcac
3841 atcttttgtg atggagagca tgcttaccca aatgcatctc atccatggga tgaggacgtc
3901 atgcctgatc ttccatacaa gacctggaaa ctttttcaat atggatatat tcctattgaa
3961 aatgaactag cagatcttga tggaaatgca gctggaggca atgctacaga aaaagcactt
4021 ctgtatcaga tgcctttttt tctacttgaa aacagtgacc accaagtact tagaactggt
4081 gagagcactg aatttacttt taactttgac tgtgaatggg ttaataatga aagagcatac
4141 attcctcctg gattgatgtt caatccaaaa gttccaacaa gaagagttca gtacataaga
4201 caaaacggaa gcacagcagc cagcacaggc agaattcagc catactcaaa accaacaagc
4261 tggatgacag gacctggcct gctcagtgca cagagagtag gaccacagtc atcagacact
4321 gctccattca tggtttgcac taacccagaa ggaacacaca taaacacagg tgctgcagga
4381 tttggatctg gctttgatcc tccaagcgga tgtctggcac caactaacct agaatacaaa
4441 cttcagtggt accagacacc agaaggaaca ggaaataatg gaaacataat tgcaaaccca
4501 tcactctcaa tgcttagaga ccaactccta tacaaaggaa accagaccac atacaatcta
4561 gtgggggaca tatggatgtt tccaaatcaa gtctgggaca gatttcctat caccagagaa
4621 aatccaatct ggtgcaaaaa accaagggct gacaaacaca caatcatgga tccatttgat
4681 ggatccattg caatggatca tcctccaggc actattttta taaaaatggc aaaaattcca
4741 gtaccaactg caacaaatgc agactcatat ctaaacatat actgtactgg acaagtcagc
4801 tgtgaaattg tatgggaagt agaaagatac gcaacaaaga actggcgtcc agaaagaaga
4861 catactgcac tcgggatgtc actgggagga gagagcaact acacgcctac ataccacgtg
4921 gatccaacag gagcatacat ccagcccacg tcatatgatc agtgtatgcc agtaaaaaca
4981 aacatcaata aagtgttgta atcttataag cctctttttt gcttctgctt acaagttcct
5041 cctcaatgga caagcggaaa gtgaagggtg actgtagtcc tgagctcatg ggttcaagac
5101 cacagcccga tggtagtggt gttaccgtct cgaacctagc cgacagccct tgtacattgt
5161 ggggggagct gttttgtttg cttatgcaat cgcgaaactc tatatctttt aatgtgt

SEQ ID NO: 2 HBoV ST2 genomic DNA
1    gccggcagac atattggatt ccaagatggc gtctgtacaa ccacgtcaca tataaaataa
61   taaatattca caaggaggag tggttatatg atgtaatcca taaccactcc caggaaatga
121  cgtatgatag ccaatcagaa ttgagtatta aacctatata agctgctgca cttcctgatt
181  caatcagact gcatccggtc tccggcgagt gaacatctct ggaaaaagct ccacgcttgt
241  ggtgagtcta ctatggcttt caatcctcct gtgattagag ctttttctca acctgctttt
301  acttatgtct tcaaatttcc atatccacaa tggaaagaaa aagaatggct gcttcatgca
361  cttttagctc atggaactga acaatctatg atacaattaa gaaactgcgc tcctcatccg
421  gatgaagaca taatccgtga tgacttgctt atttctttag aagatcgcca ttttggggct
481  gttctctgca aggctgttta catggcaaca actactctca tgtcacacaa acaaaggaat
541  atgtttcctc gttgtgacat catagttcag tctgagctag gagagaaaaa cttacactgc
601  catattatag ttgggggaga aggactaagc aagaggaatg ctaaatcatc ctgtgctcag
661  ttctatggtt taatactagc tgagataatt caacgctgca aatctcttct ggctacacgt
721  ccttttgaac ctgaggaggc tgacatattt cacactctaa aaaaggctga gcgagaggca
781  tggggtggag ttactggcgg caacatgcag atccttcaat atagagatcg cagaggagac
841  cttcatgcac aaacagtgga tcctcttcgc ttcttcaaaa actacctttt acctaaaaat
901  agatgtattt catcttacag caaacctgat gtttgtactt ctcctgacaa ctggttcatt
961  ttagctgaaa aaacttactc tcacactctt attaacgggc tgccgcttcc agaacattac
1021 agaaaaaact accacgcaac cctagataac gaagtcattc cagggcctca aacaatggcc
1081 tatggaggac gtggtccgtg ggaacatctt cctgaggtag gagatcagcg cctagctgcg
1141 tcttctgtta gcactactta taaacctaac aaaaaagaaa aacttatgct aaacttgcta
1201 gacaaatgta aagagctaaa tctattagtt tatgaagact tagtagctaa ttgtcctgaa
1261 ctactcctta tgcttgaagg tcaaccagga ggggcacgcc ttatagaaca agtcttgggc
1321 atgcaccata ttaatgtttg ttctaacttt acagctctca catatctttt tcatctacat
1381 cctgttactt cgcttgactc agacaataaa gctttacagc ttttgttgat tcaaggctat
1441 aatcctctag ccgttggtca cgccctgtgc tgtgtcctga acaaacaatt cgggaaacaa
1501 aacactgttt gcttttacgg gcctgcctca acaggtaaaa caaatatggc caaggcaatc
1561 gtccaaggga ttagacttta tgggtgtgtt aatcatttga acaaaggatt tgtatttaat
1621 gactgcagac aacgcctagt tgtttggtgg gaggagtgct taatgcacca ggattgggtg
1681 gaacctgcaa agtgtatctt gggcgggaca gaatgcagaa ttgacgtcaa gcatagagac
1741 agtgtacttt taactcaaac acctgtaatt atatccacta accacgatat ctacgcggtt
1801 gttggtggca attctgtttc tcatgttcac gcggctccat taaaagaaag agtgattcag
1861 ctaaatttta tgaaacaact tcctcaaaca tttggagaaa tcactgctac tgagattgca
1921 gctcttctac agtggtgttt caatgagtac gactgtactc tgacaggatt taaacaaaaa
1981 tggaatttag ataaaattcc aaactcattt cctcttgggg tcctttgtcc tactcattca
2041 caggacttta cacttcacga aaacggatac tgcactgatt gcggtggtta ccttcctcat
2101 agtgctgaca attctatgta cactgatcgc gcaagcgaaa ctagcacagg agacatcaca
2161 ccaagtaagt aaatacgcat gcgcaagtaa ttcttttact ttcacttcgc tatttttacc
2221 aatttttact tttaggtgac ttgggggatt cggacggaga agacaccgag cctgagacat
2281 cgcaagtgga ctattgtcca cccaagaaac gtcgtctaac tgctccagca agtcctccaa
2341 actcacctgc gagctctgta agtactatta ctttctttaa cacttggcac gcacagccac
2401 gtgacgaaga tgagctcagg gaatatgaaa gacaagcatc gctcctacaa aagaaaaggg
2461 agtccagaaa gaggggagag gaagagacac tggcagacaa ctcatcacag gagcaggagc
2521 cgcagcccga tccgacacag tggggagaga ggctcgggct catatcatca ggaacaccca
2581 atcagccacc tatcgtcttg cactgcttcg aagacctcag accaagtgat gaagacgagg
2641 gagagtacat cggggaaaaa agacaataga acaaatccat acactgtatt cagtcaacac
2701 agagcttcca atcctgaagc tccagggtgg tgtgggttct actggcactc tactcgcatt
2761 gctagagatg gtactaattc aatctttaat gaaatgaaac aacagtttca acaactacaa
2821 attgataata aaataggatg ggataacact agagaactat tgtttaatca aaagaaaaca
2881 ctagatcaaa aatacagaaa tatgttctgg cactttagaa ataactctga ttgtgaaaga
2941 tgtaattact gggatgatgt gtaccgtaga cacttagcta atgtttcctc acagacagaa
3001 gcagacgaga taactgacga ggaaatgctt tctgctgctg aaagcatgga agcagatgcc
3061 tccaattaag agacagccta gagggtgggt gctgcctgga tacagatatc ttgggccatt
3121 taatccactt gataacggtg aacctgtaaa taacgctgat cgcgctgctc aattacatga
3181 tcacgcctac tctgaactaa taaagagtgg taaaaatcca tacctgtatt tcaataaagc
3241 tgatgaaaaa ttcattgatg atctaaaaga cgattggtca attggtggaa ttattggatc
3301 cagttttttt aaaataaagc gcgccgtggc tcctgctctg ggaaataaag agagagccca
3361 aaaaagacac ttttactttg ctaactcaaa taaaggtgca aaaaaaacaa aaaaaagtga
3421 acctaaacca ggaacctcaa aaatgtctga cactgacatt caagaccaac aacctgatac
3481 tgtggacgca ccacaaaaca cctcaggggg aggaacagga agtattggag gaggaaaagg
3541 atctggtgtg gggatttcca ctggagggtg ggtcggaggt tctcactttt cagacaaata
3601 tgtggttact aaaaacacaa gacaatttat aaccacaatt cagaatggtc acctctacaa
3661 aacagaggcc attgaaacaa caaaccaaag tggaaaatca cagcgctgcg tcacaactcc
3721 atggacatac tttaacttta atcaatacag ctgtcacttc tcaccacagg attggcagcg
3781 ccttacaaat gaatataagc gcttcagacc taaagcaatg caagtaaaga tttacaactt
3841 gcaaataaaa caaatacttt caaatggtgc tgacacaaca tacaacaatg acctcacagc
3901 tggcgttcac atcttttgtg atggagagca tgcttaccca aatgcatctc atccatggga
3961 tgaggacgtc atgcctgatc ttccatacaa gacctggaaa ctttttcaat atggatatat
4021 tcctattgaa aatgaactcg cagatcttga tggaaatgca gctggaggca atgctacaga
4081 aaaagcactt ctgtatcaga tgcctttttt tctacttgaa aacagtgacc accaagtact
4141 tagaactggt gagagcactg aatttacttt taactttgac tgtgaatggg ttaacaatga
4201 aagagcatac attcctcctg gactaatgtt taatccaaaa gtcccaacaa gaagagttca
4261 gtacataaga caaaacggaa gcacagcagc cagcacaggc agaattcagc catactcaaa
4321 accaacaagc tggatgacag gacctggcct gctcagtgca caaagagtag gaccacagtc
4381 atcagacact gctccattca tggtttgcac taacccagaa ggaacacaca taaacacagg
4441 tgctgcagga tttggatctg gctttgatcc tccaaacgga tgtctggcac caactaacct
4501 agaatacaaa cttcagtggt accagacacc agaaggaaca ggaaataatg gaaacataat
4561 tgcaaaccca tcactctcaa tgcttagaga ccaactccta tacaaaggaa accaaaccac
4621 atacaatcta gtgggggaca tatggatgtt tccaaatcaa gtctgggaca gatttcctat
4681 caccagagaa aatccaatct ggtgcaaaaa accaagggct gacaaacaca caatcatgga
4741 tccatttgat ggatcaattg caatggatca tcctccaggc actattttta taaaaatggc
4801 aaaaattcca gttccaactg cctcaaatgc agactcatac ctaaacatat actgtactgg
4861 acaagtcagc tgtgaaattg tatgggaggt agaaagatac gcaacaaaga actggcgtcc
4921 agaaagaaga catactgcac tcgggatgtc actgggagga gagagcaact acacgcctac
4981 ataccacgtg gatccaacag gagcatacat ccagcccacg tcatatgatc agtgtatgcc
5041 agtaaaaaca aacatcaata aagtgttgta atcttataag cctctttttt gcttctgctt
5101 acaagttcct cctcaatgga caagcggaaa gtgaagggtg actgtagtcc tgagctcatg
5161 ggttcaagac cacagcccga tggtagtggt gttaccgtct cgaacctagc cgacagccct
5221 tgtacattgt ggggggagct gttttgtttg cttatgcaat cgcgaaactc tatatctttt
5281 aatgtgttgt tgttgtaca

SEQ ID NO: 3 HBoV NS1 polypeptide encoded by nt
183-2101 of SEQ ID NO: 1 and nt 253-2172 of
SEQ ID NO: 2
MAFNPPVIRAFSQPAFTYVFKFPYPQWKEKEWLLHALLAHGTEQSMIQLR
NCAPHPDEDIIRDDLLISLEDRHFGAVLCKAVYMATTTLMSHKQRNMFPR
CDIIVQSELGEKNLHCHIIVGGEGLSKRNAKSSCAQFYGLILAEIIQRCK
SLLATRPFEPEEADIFHTLKKAEREAWGGVTGGNMQILQYRDRRGDLHAQ
TVDPLRFFKNYLLPKNRCISSYSKPDVCTSPDNWFILAEKTYSHTLINGL
PLPEHYRKNYHATLDNEVIPGPQTMAYGGRGPWEHLPEVGDQRLAASSVS
TTYKPNKKEKLMLNLLDKCKELNLLVYEDLVANCPELLLMLEGQPGGARL
IEQVLGMHHINVCSNFTALTYLFHLHPVTSLDSDNKALQLLLIQGYNPLA
VGHALCCVLNKQFGKQNTVCFYGPASTGKTNMAKAIVQGIRLYGCVNHLN
KGFVFNDCRQRLVVWWEECLMHQDWVEPAKCILGGTECRIDVKHRDSVLL
TQTPVIISTNHDIYAVVGGNSVSHVHAAPLKERVIQLNFMKQLPQTFGEI
TATEIAALLQWCFNEYDCTLTGFKQKWNLDKIPNSFPLGVLCPTHSQDFT
LHENGYCTDCGGYLPHSADNSMYTDRASETSTGDITPSK

SEQ ID NO: 4 HBoV NP-1 polypeptide encoded by nt
2340-2999 of SEQ ID NO: 1 and nt 2410-3069 of
SEQ ID NO: 2
MSSGNMKDKHRSYKRKGSPERGERKRHWQTTHHRSRSRSPIRHSGERGSG
SYHQEHPISHLSSCTASKTSDQVMKTRESTSGKKDNRTNPYTVFSQHRAS
NPEAPGWCGFYWHSTRIARDGTNSIFNEMKQQFQQLQIDNKIGWDNTREL
LFNQKKTLDQKYRNMFWHFRNNSDCERCNYWDDVYRRHLANVSSQTEADE
ITDEEMLSAAESMEADASN

SEQ ID NO: 5 HBoV ST1 VP1 polypeptide encoded by
nt 2986-5001 of SEQ ID NO: 1
MPPIKRQPRGWVLPGYRYLGPFNPLDNGEPVNNADRAAQLHDHAYSELIK
SGKNPYLYFNKADEKFIDDLKDDWSIGGIIGSSFFKIKRAVAPALGNKER
AQKRHFYFANSNKGAKKTKKSEPKPGTSKMSDTDIQDQQPDTVDAPQNAS
GGGTGSIGGGKGSGVGISTGGWVGGSHFSDKYVVTKNTRQFITTIQNGHL
YKTEAIETTNQSGKSQRCVTTPWTYFNFNQYSCHFSPQDWQRLTNEYKRF
RPKAMQVKIYNLQIKQILSNGADTTYNNDLTAGVHIFCDGEHAYPNASHP
WDEDVMPDLPYKTWKLFQYGYIPIENELADLDGNAAGGNATEKALLYQMP
FFLLENSDHQVLRTGESTEFTFNFDCEWVNNERAYIPPGLMFNPKVPTRR
VQYIRQNGSTAASTGRIQPYSKPTSWMTGPGLLSAQRVGPQSSDTAPFMV
CTNPEGTHINTGAAGFGSGFDPPSGCLAPTNLEYKLQWYQTPEGTGNNGN
IIANPSLSMLRDQLLYKGNQTTYNLVGDIWMFPNQVWDRFPITRENPIWC
KKPRADKHTIMDPFDGSIAMDHPPGTIFIKMAKIPVPTATNADSYLNIYC
TGQVSCEIVWEVERYATKNWRPERRHTALGMSLGGESNYTPTYHVDPTGA
YIQPTSYDQCMPVKTNINKVL

SEQ ID NO: 6 HBoV ST1 VP2 polypeptide encoded by
nt 3373-5001 of SEQ ID NO: 1
MSDTDIQDQQPDTVDAPQNASGGGTGSIGGGKGSGVGISTGGWVGGSHFS
DKYVVTKNTRQFITTIQNGHLYKTEAIETTNQSGKSQRCVTTPWTYFNFN
QYSCHFSPQDWQRLTNEYKRFRPKAMQVKIYNLQIKQILSNGADTTYNND
LTAGVHIFCDGEHAYPNASHPWDEDVMPDLPYKTWKLFQYGYIPIENELA
DLDGNAAGGNATEKALLYQMPFFLLENSDHQVLRTGESTEFTFNFDCEWV
NNERAYIPPGLMFNPKVPTRRVQYIRQNGSTAASTGRIQPYSKPTSWMTG
PGLLSAQRVGPQSSDTAPFMVCTNPEGTHINTGAAGFGSGFDPPSGCLAP
TNLEYKLQWYQTPEGTGNNGNIIANPSLSMLRDQLLYKGNQTTYNLVGDI
WMFPNQVWDRFPITRENPIWCKKPRADKHTIMDPFDGSIAMDHPPGTIFI
KMAKIPVPTATNADSYLNIYCTGQVSCEIVWEVERYATKNWRPERRHTAL
GMSLGGESNYTPTYHVDPTGAYIQPTSYDQCMPVKTNINKVL

SEQ ID NO: 7 HBoV ST2 VP1 polypeptide encoded by
nt 3056-5071 of SEQ ID NO: 2
MPPIKRQPRGWVLPGYRYLGPFNPLDNGEPVNNADRAAQLHDHAYSELIK
SGKNPYLYFNKADEKFIDDLKDDWSIGGIIGSSFFKIKRAVAPALGNKER
AQKRHFYFANSNKGAKKTKKSEPKPGTSKMSDTDIQDQQPDTVDAPQNTS
GGGTGSIGGGKGSGVGISTGGWVGGSHFSDKYVVTKNTRQFITTIQNGHL
YKTEAIETTNQSGKSQRCVTTPWTYFNFNQYSCHFSPQDWQRLTNEYKRF
RPKAMQVKIYNLQIKQILSNGADTTYNNDLTAGVHIFCDGEHAYPNASHP
WDEDVMPDLPYKTWKLFQYGYIPIENELADLDGNAAGGNATEKALLYQMP
FFLLENSDHQVLRTGESTEFTFNFDCEWVNNERAYIPPGLMFNPKVPTRR
VQYIRQNGSTAASTGRIQPYSKPTSWMTGPGLLSAQRVGPQSSDTAPFMV
CTNPEGTHINTGAAGFGSGFDPPNGCLAPTNLEYKLQWYQTPEGTGNNGN
IIANPSLSMLRDQLLYKGNQTTYNLVGDIWMFPNQVWDRFPITRENPIWC
KKPRADKHTIMDPFDGSIAMDHPPGTIFIKMAKIPVPTASNADSYLNIYC
TGQVSCEIVWEVERYATKNWRPERRHTALGMSLGGESNYTPTYHVDPTGA
YIQPTSYDQCMPVKTNINKVL

SEQ ID NO: 8 HBoV ST2 VP2 polypeptide encoded by
nt 3343-5071 of SEQ ID NO: 2
MSDTDIQDQQPDTVDAPQNTSGGGTGSIGGGKGSGVGISTGGWVGGSHFS
DKYVVTKNTRQFITTIQNGHLYKTEAIETTNQSGKSQRCVTTPWTYFNFN
QYSCHFSPQDWQRLTNEYKRFRPKAMQVKIYNLQIKQILSNGADTTYNND
LTAGVHIFCDGEHAYPNASHPWDEDVMPDLPYKTWKLFQYGYIPIENELA
DLDGNAAGGNATEKALLYQMPFFLLENSDHQVLRTGESTEFTFNFDCEWV
NNERAYIPPGLMFNPKVPTRRVQYIRQNGSTAASTGRIQPYSKPTSWMTG
PGLLSAQRVGPQSSDTAPFMVCTNPEGTHINTGAAGFGSGFDPPNGCLAP
TNLEYKLQWYQTPEGTGNNGNIIANPSLSMLRDQLLYKGNQTTYNLVGDI
WMFPNQVWDRFPITRENPIWCKKPRADKHTIMDPFDGSIAMDHPPGTIFI
KMAKIPVPTASNADSYLNIYCTGQVSCEIVWEVERYATKNWRPERRHTAL
GMSLGGESNYTPTYHVDPTGAYIQPTSYDQCMPVKTNINKVL

SEQ ID NO: 9 Primer 188F
GAGCTCTGTAAGTACTATTAC

SEQ ID NO: 10 Primer 542R
CTCTGTGTTGACTGAATACAG

REFERENCES

• 1 Young N S, Brown K E. Parvovirus B19. N Engl J Med 2004; 350(6):586-97.
• 2 Jones M S, et al., J Virol 2005; 79(13):8230-6.
• 3 Allander T. et al., PNAS USA 2001; 98:11609-14
• 4 Allander T. et al., PNAS USA 2005; 102(36):12891-12896.
• Schwartz, D., et al., (2002) Virology 302, 219-23.
• 6 Chen, K. C., et al., (1986) J Virol 60, 1085-97
• 7 Deiman B, van Aarle P & Sillekens P, Molecular Biotechnology 2002, 20:163-178.
• 8 U.S. Pat. No. 4,683,195
• 9 Mullis et al. Cold Spring Harbor Symp. Quant. Biol., 51:263,
• 10 Ehrlich (ed), PCR technology, Stockton Press, NY, 1989
• 11 Ehrlich et al. Science, 252:1643-1650, 1991
• 12 “PCR protocols; A Guide to Methods and Applications”, Eds. Innis et al. Academic Press, New York, 1990.
• 13 Kontermann, R & Dubel, S, Antibody Engineering, Springer-Verlag New York, LLC; 2001, ISBN: 3540413545.
• 14 WO92/01047
• Mendez, M. et al. (1997) Nature Genet, 15(2): 146-156
• 16 Nygren et al. (1997) Current Opinion in Structural Biology, 7: 463-469.
• 17 WO/0034784

Claims

1. A method of testing a sample for the presence of a human bocavirus, comprising testing the sample for the presence or absence of at least one molecule selected from the group consisting of:

a) a nucleic acid sequence comprising a nucleotide sequence of a ST2 isolate of human bocavirus of SEQ ID NO: 2;

b) a bocaviral nucleic acid molecule that encodes a VP1 polypeptide of human bocavirus ST2 of SEQ ID NO: 7

c) a nucleic acid molecule comprising a nucleotide sequence that encodes a polypeptide having at least 95% sequence identity with the human bocavirus ST2 polypeptide VP1 of SEQ ID NO: 7; and

d) a nucleic acid molecule comprising a nucleotide sequence that has at least 95% sequence identity with the ST2 isolate of SEQ ID NO: 2.

2. A method of testing a sample for the presence or absence of antibodies to human bocavirus, comprising determining whether antibodies in the sample bind to at least one polypeptide encoded by a nucleic acid selected from the group consisting of

a) a nucleic acid sequence comprising a nucleotide sequence of a ST2 isolate of human bocavirus of SEQ ID NO: 2;

b) a bocaviral nucleic acid molecule that encodes a VP1 polypeptide of human bocavirus ST2 of SEQ ID NO: 7;

c) a nucleic acid molecule comprising a nucleotide sequence that encodes a polypeptide having at least 95% sequence identity with the human bocavirus ST2 polypeptide VP1 of SEQ ID NO: 7; and

d) a nucleic acid molecule comprising a nucleotide sequence that has at least 95% sequence identity with the ST2 isolate of SEQ ID NO: 2.

3. A method according to claim 2, comprising performing an enzyme immunoassay to detect binding of antibodies in the sample to the polypeptide.

4. A kit for testing a sample for the presence of absence of antibodies to human bocavirus, comprising a polypeptide attached to a support wherein the polypeptide is encoded by a nucleic acid selected from the group consisting of

a) a nucleic acid sequence comprising a nucleotide sequence of a ST2 isolate of human bocavirus of SEQ ID NO: 2;

b) a bocaviral nucleic acid molecule that encodes a VP1 polypeptide of human bocavirus ST2 of SEQ ID NO: 7;

c) a nucleic acid molecule comprising a nucleotide sequence that encodes a polypeptide having at least 95% sequence identity with the human bocavirus ST2 polypeptide VP1 of SEQ ID NO: 7; and

d) a nucleic acid molecule comprising a nucleotide sequence that has at least 95% sequence identity with the ST2 isolate of SEQ ID NO: 2, wherein said kit further comprises an anti-immunoglobulin antibody molecule linked to an enzyme that catalyzes conversion of a substrate to a detectable product, and a substrate for the enzyme.

5. A method of testing a sample for the presence or absence of a human bocavirus, comprising testing the sample for the presence of at least one nucleic acid molecule consisting of an isolated fragment of sequence SEQ ID NO: 2, wherein the fragment is selected from the group consisting of:

a) nucleotides 253 to 2172 of SEQ ID NO:2;

b) nucleotides 2410 to 3069 of SEQ ID NO:2;

c) nucleotides 3056 to 5071 of SEQ ID NO:2;

d) nucleotides 3443 to 5071 of SEQ ID NO:2;

e) a nucleotide sequence with at least 95% sequence identity with the isolated fragment of a), b), c) or d).

6. A method of testing a sample for the presence or absence of a human bocavirus, wherein the method comprises testing the sample for the presence of at least one isolated polypeptide encoded by a bocavirus nucleic acid, wherein the polypeptide is selected from the group consisting of:

a) a human bocavirus ST2 polypeptide VP1 of SEQ ID NO: 7;

b) a human bocavirus ST2 polypeptide VP2 of SEQ ID NO: 8;

c) a human bocavirus ST2 polypeptide NP1 of SEQ ID NO: 4;

d) a human bocavirus ST2 polypeptide NS1 of SEQ ID NO: 3; and

e) a human bocavirus ST2 polypeptide having at least 95% sequence identity with the human bocavirus ST2 polypeptides of a), b), c) or d).